Hi again! Thought I'd post the 1,000 LED Sequencer schematic. It shows enough of the schematic to see how it is done. It could potentially go even higher, say 1,000,000 ! Anyway, anyone care to build it! Hehe.

Thanks MrAl. Looks good. As you can see it requires 3 - 4017 Ic's and 1 - 555 timer. The thing I wish I could do yet is reduce the number transistors it requires, which is 110! It also needs 120-resistors.

It would take someone a long time to build this, just because of all the wiring required. It still could be expanded to 1,000,000 or more with an additional 4017 IC. However, it would require over 100,000 transistors! Sheez!

The 33 I/O ucontroller would be much better using Charlieplexing. I did figure out how it would be wired up, and the programming wouldn't be too bad, but again that's a lot of wiring and LEDs!

Keep in mind, that there is only about 8ma flowing at any given time through this whole maze of LEDs.

MrAl, my circuit requires a transistor for every bank of 10 LEDs. I haven't been able to figure out how to reduce that number. For 1,000 LEDs I need 100 transistors for 100 banks, and I need another transistor for every group of 10 banks, for a total of 110 transistors.

Anyway, if anyone can come up with a circuit using less parts, I would like to see it. I wouldn't mind adding another IC, if it would eliminate most of the transistors.

I wish it were that simple MrAl. Remember, we only want one LED ON at a time. I don't know of any IC's that can be cascaded allowing only one LED to light at a time, throughout the sequence of 1,000 LEDs. It has been a challenge (puzzle) that I work on from time to time.

Well, if i were building an array of LEDs that had 1000 LEDs in it
i would make sure i could turn them on any way i choose, but since
you seem to be happy with limiting the operation to one LED at a
time then almost any means of multiplexing is possible.
For example, 32 ports horizontally and 32 ports vertically provides
for 1024 LED signals, which get turned on via a microcontroller
and port expanders.
Or did you say you dont want to use a microcontroller?

That was nice of you to offer MrAl, but I really want to stay with non-programmable ICs for this one.

I believe that so many beginners(and amateurs) would like to stay away from programming to start with. I want them to be able to build the circuits that I design,fairly easily, then later when they find out how a ucontroller can reduce the part-count considerably, they will automatically switch to them as well.